<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>几何模型</title>
		<style type="text/css">
			.box {
				width: 300px;
				height: 300px;
				background-color: #000000;
				color: #FFFFFF;
				text-align: center;
				line-height: 300px;
				font-size: 50px;
			}
			.box1 {
				width: 300px;
				height: 300px;
				background-color: #000000;
				border-radius: 50%;
				color: #FFFFFF;
				text-align: center;
				line-height: 300px;
				font-size: 50px;
			}
			.box2 {
				width: 300px;
				height: 300px;
				background-color: #000000;
				border-radius: 100px 200px;
				color: #FFFFFF;
				text-align: center;
				line-height: 300px;
				font-size: 50px;
			}
			.box3 {
				width: 0;
				height: 0;
				border-top: 300px solid transparent;
			   border-left: 300px solid #FF0000;
				border-right: 300px solid transparent;
				border-bottom: 300px solid transparent;
				color: #FFFFFF;
				text-align: center;
				line-height: 300px;
				font-size: 50px;
				position: relative;
			}
			.box3::after {
				content: '三角形';
				position: absolute;
				display: block;
				/* background-color: #0000FF; */
				width: 100px;
				height: 50px;
				top: -163px;
				left: -280px;
				color: #FFFFFF;
			}
			.box4 {
				width: 120px;
				height: 120px;
				border-top: 300px solid transparent;
				border-bottom: 300px solid #FF0000;
				border-right: 300px solid transparent;
				border-left: 300px solid transparent;
				color: #FFFFFF;
				text-align: center;
				line-height: 300px;
				font-size: 50px;
			}
		</style>
	</head>
	<body>
		<div class="box">方形</div>
		<div class="box1">圆形</div>
		<div class="box2">椭圆形</div>
		<div class="box3"></div>
		<div class="box4">梯形</div>
	</body>
</html>
